Ancient philosophers and contemporary scientists agree: strong social ties are a key — arguably the key — to happiness. You need close, long-term relationships; you need to be able to confide in others; you need to belong; you need to get and give support. Studies show that if you have five or more friends with whom to discuss an important matter you’re far more likely to describe yourself as “very happy.”

Not only does having strong relationships make it far more likely that you take joy in life, but studies show that it also lengthens life (incredibly, even more than stopping smoking), boosts immunity, and cuts the risk of depression.

But making friends can be difficult. Here are some strategies to try, if you are eager to make friends but finding it tough:

1. Show up. Just as Woody Allen said that “Eighty percent of success is showing up,” a big part of friendship is showing up. Whenever you have the chance to see other people, take it. Go to the party. Stop by someone’s desk. Make the effort. I’m a big believer in the power of online tools like Facebook, Twitter, and Google+ to help sustain relationships, but nothing can replace a face-to-face meeting.

Also, the mere exposure effect describes the fact that repeated exposure makes you like someone better – and makes that person like you better, too. You are much more likely to become friends with someone if you see him or her often. You may become close to unlikely people, just because circumstances put you in constant contact.